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Draw a graph depicting a skydivers speed against time when jumping from a plane, until he deploys his parachute, explaining the logic of your answer through the forces applicable to the body.

Upon jumping from the plane, the diver experiences three forces; a downward force from his weight; opposed by a lift force (equal to the weight of the air he displaces); and an upward drag force = ½ . (C D. ...
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Answered by Bronagh R. • Physics tutor
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Derive an expression for wave speed in terms of wavelength and frequency.

The general expression for speed is speed=distance/time.The wavelength (lambda) of a wave is the distance between one point on an oscillation to the exact same point on the next oscillation, or more simply t...
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Answered by Muhammed R. • Physics tutor
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What is the difference between alpha and gamma radiation?

Alpha radiation is a type of radiaiton which has a high ionisation and low penetration. This means it can ionise objects very easily (so can be more damaging to humans) but it can only travel a very short di...
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Answered by Austin D. • Physics tutor
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How do I derive Kepler's 3rd law using Newton's Law of gravitation, in the case of a circular orbit?

Kepler's 3rd law states that the cube of the radius, r from a planet is directly proportional to the square of the orbital period around it, T: r 3 ∝ T 2 (this is the result we want!) We know Newton's Law of...
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Answered by Greta C. • Physics tutor
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When going around a roundabout, why do I feel a force pulling me outwards?

The force pulling you outwards is what is called fictional force. Actually, there is a force pulling the car inwards and since Newton's Laws mean that you want to keep moving forwards rather than going aroun...
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Answered by Jasmine C. • Physics tutor
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